126 BULLETIN 76, UNITED STATES NATIONAL MUSEUM. 



ous. Ahiicluial iK'dicellaiiffi present on the disk; about ten papulae to each area; 

 afewintermai<rinal pedicelhiriff; only two or three actinal interradial pediceliarise, 

 and none on inferomarginals or adambulacrals. Furrow spinelets, five to seven; 

 oidarged actinal mouth spine relatively larger than in adult; furrow spinelets of 

 mouth plates about five. Madreporic bofly nearly touches the marginals, only one 

 row of pa.xillse intervening. 



Ttjpe.— Cat. No. 27798, U.S.N.M. 



Type-locality.— Albatross station 4387, off San Diego, longitude of Point Con- 

 ception, 1,059 fatiioms, green mud. 



Distribution. — Known only from southern California, 984 to 1,059 fathoms; 

 undoubtedly ranging southwaid, where intergradation with P. agassizi is probable. 

 Typical agassizi ranges from the Galapagos Islands to the Gulf of California 

 (Lud%vig, 1905). 



Specimens examined. — Albatross station 2919, off Cortez Bank (latitude of San 

 Diego, California), 984 fathoms, gray mud, 218 specimens; station 4387, off San 

 Diego on longitude of Point Conception, 1,059 fathoms, green mud, 9 specimens; 

 total, 227 specimens. 



Remarlcs. — Tliis form is distuiguished from mimicus, which was dredged by the 

 Challenger in the Arafura Sea, northwest of the Am Islands, by the presence in 

 adult and moderately young specimens of abactinal, intei'marginal, and much more 

 abundant actinal pedicellarise. The papularia are larger and contain many more 

 pores. For instance P. mimicus with R ecjualling 78 mm. has but a dozen pores to 

 each papularium, wliile evoplus has fort\' to seventy-five. In P. evoplus the furrow 

 spinelets are slenderer and curved, and the spine on the actinal surface of each 

 adambulacral plate is not so prominent as in mimicus, while the proximal infero- 

 marginals are more heavily armed than in mimicus. 



Ludwig regards P. forcipatus (Sladen) as synonymous with P. Jilfioli Perrier. 

 Judging from Sladen's figures and description the papularia oi flholi are small and 

 the abactinal pedicellarise have shorter spinelets and are differently formed (less 

 pectinate than usually in evoplus), the paxiUae have stouter spinelets, and the 

 central spinelet is short and conical. The paxillse of evoplus are more nearly fike 

 those of mimicus. Other differnces to be considered are: secondary superomar- 

 ginal spinule in evoplus, none in flltoli; more numerous and prominent secondary 

 spinules on proximal inferomarginal plates in evoplus, and the furrow spinelets 

 longer, slenderer, and curved. Judging from Sladen's figures the actinal pedicel- 

 larise of flholi have shorter and more pointed spmelets than in evoplus, and the 

 intermarginal pediceUaria; of the latter are absent in. flholi (although that species 

 proximally has a few pedicellarise on the vertical sutures between the superomar- 

 ginals). 



Through the kindness of Professor lAidwig I have received for comparison a 

 specimen of P. agassizi from Albatross station 3366 (near Cocos Island). In this 

 example R = 67 mm. Although t he form here described is close to agassizi, the differ- 

 ences already mentioned seem sufficient to warrant its separation as a distinct race. 

 The proximity of the known ranges of the two forms (as well as the range m depth) 

 points to their probable intergradation. In the specimen of agassizi examined 

 the papular areas are only one-half to two-thirds as large as in evoplus and 



